Motor with relatively rotatable stator and rotor

ABSTRACT

The &#39;&#39;&#39;&#39;stator&#39;&#39;&#39;&#39; of a polyphase a.c. motor is rotatably mounted in a base and arranged to drive a first pump and the rotor to drive both the load of the motor and a second pump. By valve arrangements, the pump outputs create varying back-pressures which control the relative speeds of rotation of the rotor and stator, and thus the speed of rotation of the shaft driving the load is varied.

United States Patent 1191 Cherwink, deceased Inventor:

MOTOR WITH RELATIVELY ROTATABLE STATOR AND ROTOR Homer E. Cherwink,deceased, late of 1515 Fowler Cr. Road, Sonoma, Calif. 95476 Hazel O.Cherwink, administratrix Filed: June 1, 1971 Appl. No.: 148,576

us. 01 ..3 10/119 Int. (:1. ..H02k 23/60 Field of Search .310/115, 1 8,119;

References Cited UNITED STATES PATENTS 4/1959 Banning .310/119 [451 Apr.10, 1973 2,249,671 7/1941 Skowron ..3l0/1 19 Primary Examiner-D. F.Duggan Attorney-Julian Caplan and Gregg, Hendricson & Caplan [-57]ABSTRACT The stator of a polyphase a.c. motor is rotatably mounted in abase and arranged to drive a first pump and the rotor to drive both theload of the motor and a second pump. By valve arrangements, the pumpoutputs create varying back-pressures which control the relative speedsof rotation of the rotor and stator, and

thus the speed ofrotation of the shaft driving the load is varied.

3 2 ClaimsQl Drawing Figure PAIENIEDAPRIOIQIS 3 7, 0

III I Isltll' I I l I! lllllll INVENTOR. HOMER E. CHERWI NK ATTORNEYstages as is true sociated stator windings are rotatably mountedrelative to a stationarybase and the rotor is rotatable both relative tothe base and to the casing and stator. The casing and rotor aredrivingly connected to a pair of positive displacementpumps and theoutlet of each pump is valve controlled so that the back pressure ofeach pump may be, adjusted in an inversely proportional relationship.Thus, the speed of rotation of the drive shaft is varied by adjustmentof the valves in the outputs of the two pumps.

A principal feature of the present invention is the fact that the speedof rotation of the load may be varied from zero to a'maximum at thecontrol of the'operatorby mechanical means. It is a further feature ofthe invention that full torque is delivered at all such speeds. It willbe understood that the valve settings may be remotely controlled, orautomatically controlled, as desired. Hence, a particular-featureandadvantage of the invention is the simplicity by which the speedvariationsare controlled.

' Another feature of the invention is the fact that the graduations ofspeeds are continuous'rather than in in certain other types ofspeedcontrols for motors.

which are rotatably mounted in bearings 23 in ends 17.

The interior of casing 21 is provided with windings for stator 24 whichrotate therewith.

Motor shaft 26 is rotatable within casing 21 and provided with a rotor27 which cooperates with the stator 24 to drive shaft 26 as is wellunderstood in the the casing 21. Slip rings 31 are provided externallyof casing 21 and are contacted by brushes 32. The number of slip ringsdepends upon the winding of the motor. In this respect, the motor isconventional. Thus a three-phase motor is illustrated, such a motortending to be synchronous when mounted in conventional manner but herebeing adjustable in speed of rotation of shaft 26 as hereinafterappears.

;Mounted to be driven by the rotation of casing 21 is a first positivedisplacement pump 36. In the accompanying drawings, said pump 36 isshownlocated on top 18 but it will be understood that the pump could bedire'ctly'connected to one of the end protrusions 22 or be otherwisedriven by rotation of the casing 21. Similarly, a second pump 37,similar to pump 36, is

j mounted on top 18. The pumps 36, 37'are preferably Anotherfeature ofthe invention is the fact that the I number of parts which are subjectto maintenance and wear is reduced to a minimum. v

A still further feature of the invention is'the economy and efficiencyof the device in' that no power is diverted, as is the case in othertypes of speed controls. In many other speed controls power isdissipated in heat by use of resistance elements. v l

A still further feature of the invention is the fact that the overallweight of the controls for the motor is reduced. A common type ofspeedcontrol, which the present invention is intended to replace, is themotor generator set commonly used in driving elevators, winches, etc.,thereby eliminatingthe necessity of converting to D. C. power toaccomplish variable speed controls. The present inventionhas'considerably lesser size and weight as contrasted with suchequipment.

Another feature of the invention is the provision of automatic overloadprotection which consists of a bypass around the pump valves, a featurewhich is particularly useful when there is an extreme speed reduction oroverload which otherwise might damage the motor.

' Other objects of the present invention will become apparent uponreading the following specification and referring to the accompanyingdrawings in which similar characters of reference representcorresponding parts in each of the several views.

In the drawings:

The single FIGURE is a schematic, vertical, sectional gear type pumpsand are also preferably reversible, a type commercially available. Inthe drive shown in the accompanying drawing, separate gear trains 38 are'used to drive the shafts of pump 36 from .one end protrusion 22, ofcasing 21 and of pump 37 from shaft 26. As has been stated, other drivemeans may be em- .ployed, such as direct connection. It will further beunderstood, that the shaft 26 is attached to the load of the motor andthe speed of rotation of the load is variable;

A hydraulic fluid reservoir 41 is provided and is connected by conduits42 to the intake of pumps 36, 37.

.The outlets of said pumps are connected by separate conduits 43 back tothe reservoir 41. A valve 44 positioned in the conduit of the first pump36 is provided as is a valve 46 in the conduit 43 of thesecond pump 37.The valves 44, 46 are by-passed by conduits 47 in which are locatedby-pass valves 48 which open when the pressure in conduits 43 exceeds apredetermined view through the motor and its associated mechanismmaximum which prevents overload of the motor.

A control 51 is provided and connected by valve gear 52 to the valves44, 46. It will be understood that remote control, or automatic control,can be substituted. 1 g v To commence operation of the motor, the lever51 is positioned in stop position with valve 46 closed so as to restrainrotation of pump 37. Hence, rotor 27 does not turn. In this position ofthe valve control 51, valve 44 is full open, thus allowing pump 36 toturn freely. In this positioning of lever 51, stator 24 revolves at themaximum rate of speed for which the motor is wound. After the motor hasstarted, lever 51 is adjusted so that valve 46 is partially opened andvalve 44 is closed in'a proportionate amount. As valve 46 opens a smallamount, the pump 36 is partially restricted and the turning of thestator 24 islikewise partially restricted. The stator 24 continues to beincreasingly restricted while the rotor 27 increases in its speed asvalve 46 is opened wider. At full speed position of lever 51, the statorvalve 44 is completely closed, thereby stopping the tor.

' rotation of pump 36 and of the casing 21 and stator 24,

At this position, valve 46 is full-open, allowing free flow of fluidfrom pump 37(Therotor 27 is then turning at the m'aximumdesign speed ofthe operation of the mo- At the loadcapacity of the motor, when thepressure in' one of the lines 43 exceeds a predetermined amount,

3 by-pass valves 48" open. This'prevents overloading of the motorbecause of an improperlyfast movement of ope'n'under extreme retar-'levers 1. Also, the valves 48 dation'and overload.

' -It is possible to reverse the-motor electrically by motor switchingmeans well understood in the A.C.

motor art provided the pumps 36, 37 are reversible so as not 'to affectthe flow of fluid.

Brakes 56 may be used at full speed to lock the stator; At positive stopthe brakes compensate for internal leakage of the pumps.

Whatisclaimedis: I I

. 1.;A variablespeed synchronous motor control comprising a base, astator, mounting means for said stator rotatably mounted in said base, arotor, a shaft for said second pumps respectively, a valve gear connectedto said valves whereby when one said valve is opened the other saidvalve is closed a proportional amount, by-

, pass conduits around each said valve and a pressure re.-

lief valve in each said conduit.

2. A motor control according to claim 1 which further comprises a firstgear train between said mounting means and said first pump and a secondgear train between said shaft and'said second pump.

1. A variable speed synchronous motor control comprising a base, astator, mounting means for said stator rotatably mounted in said base, arotor, a shaft for said rotor rotatably mounted in said mounting means,said stator and rotor when electrically energized turning said shaftrelative to said stator, a first positive displacement pump drivinglyconnected for rotation with said mounting means, a second positivedisplacement pump drivingly connected for rotation with said shaft, areservoir for said pumps, a first valve and a second valve regulatingvolume of discharge from said first and second pumps respectively, avalve gear connected to said valves whereby when one said valve isopened the other said valve is closed a proportional amount, bypassconduits around each said valve and a pressure relief valve in each saidconduit.
 2. A motor control according to claim 1 which further comprisesa first gear train between said mounting means and said first pump and asecond gear train between said shaft and said second pump.